Composite transition fitting

ABSTRACT

A pipe fitting having a first body and a second body that together at least partially define a fluid flow passage. The first body defines a first portion of the fluid flow passage that extends from a first end of the fluid flow passage to a first internal opening. The second body defines a second portion of the fluid flow passage that extends from a second internal opening to a second end of the fluid flow passage. The first body has a first interface surface that surrounds the first internal opening, the first interface surface having a plurality of anti-rotation grooves. The second body has a second interface surface that surrounds the second internal opening and engages with the first interface surface. The first internal opening is in fluid communication with the second internal opening. The second interface surface has a plurality of anti-rotation fingers that are each received by and engage with a corresponding one of the anti-rotation grooves. Rotation of the second body relative to the first body is resisted by the engagement of the anti-rotation fingers with the anti-rotation grooves.

FIELD OF THE INVENTION

This invention relates to pipe fittings, and more particularly tocomposite transition fittings.

BACKGROUND OF THE INVENTION

Transition fittings are known in the prior art for fluidly connectingpipes that are made from different materials, such as metallic pipes andpolymeric pipes. Transition fittings often incorporate a threadedportion, which may be made from a metal such as brass, and anon-threaded portion, which may be made from a polymeric material. Thethreaded portion may, for example, be adapted for attaching to athreaded metallic pipe, and the non-threaded portion may, for example,be adapted for attaching to a non-threaded polymeric pipe. When thefitting is installed between a metallic pipe and a polymeric pipe, thefitting allows fluid, such as water, to flow through the fitting fromthe metallic pipe to the polymeric pipe, or vice versa.

A disadvantage of transition fittings that incorporate metalliccomponents, and in particular brass, is that machined brass componentscan be very expensive. Furthermore, brass often contains lead, which mayleach into the water and potentially cause a health hazard. In addition,fittings that contain dissimilar metallic and polymeric materials mayhave an increased risk of leaking, due to a number of factors, includingthe wide spread in coefficients of thermal expansion of the differentmaterials.

Transition fittings that are made from polymeric materials only are alsoknown in the prior art. For example, U.S. Pat. No. 8,172,275 to Sumrall,Jr. et al., issued May 8, 2012, teaches a composite polymeric transitionpipe fitting that includes a tubular main fitting body with a secondarytubular polymeric body that is molded into the main body, such that themain body extends around the secondary body.

A disadvantage of the transition fitting disclosed in U.S. Pat. No.8,172,275 to Sumrall, Jr. et al. is that, because the secondary tubularpolymeric body is molded into the main body, the dimensions of thesecondary tubular polymeric body are limited by the dimensions of themain body.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved type ofpipe fitting that at least partially overcomes some of the disadvantagesof the prior art.

Accordingly, in one aspect the present invention resides in a pipefitting comprising: a first body and a second body that together atleast partially define a fluid flow passage; the first body defining afirst portion of the fluid flow passage that extends from a first end ofthe fluid flow passage to a first internal opening; the second bodydefining a second portion of the fluid flow passage that extends from asecond internal opening to a second end of the fluid flow passage;wherein the first body has a first interface surface that surrounds thefirst internal opening, the first interface surface having a pluralityof anti-rotation grooves; wherein the second body has a second interfacesurface that surrounds the second internal opening and engages with thefirst interface surface, the first internal opening being in fluidcommunication with the second internal opening, and the second interfacesurface having a plurality of anti-rotation fingers that are eachreceived by and engage with a corresponding one of the anti-rotationgrooves; and wherein rotation of the second body relative to the firstbody is resisted by the engagement of the anti-rotation fingers with theanti-rotation grooves.

At least one advantage of the pipe fitting according to at least someembodiments of the present invention is that the anti-rotation fingersand anti-rotation grooves may improve the connection between the firstand second bodies, which helps the fitting withstand the rotationalforces that may be experienced during installation or removal of thefitting.

Furthermore, in at least some preferred embodiments, the arrangement ofthe anti-rotation grooves on the first interface surface allows thesecond body to be overmolded over the first body. This allows the secondbody to extend away from the first body, and to be formed in a shapethat is at least partially independent of the shape of the first body.For example, in some embodiments of the invention, the second body maybe formed to incorporate a spigot or a socket, without requiring anycorresponding changes to the shape or size of the first body. Thisincreases the number of manufacturing options that are available, andfor example would allow a single molded shape of the first body to beused in conjunction with any number of different molds for the secondbody, providing spigots and sockets of various shapes and sizes.

Preferably, the first body has a cylindrical wall with a cylindricalouter surface and a cylindrical inner surface, and the first interfacesurface is a ring-shaped end surface of the cylindrical wall that spansbetween the cylindrical outer surface to the cylindrical inner surface.The cylindrical wall preferably includes an overlapping portion wherethe second body is overmolded over the first body. The first body alsopreferably includes a non-overlapping portion which is spaced from thesecond body. The non-overlapping portion may, for example, include amale or female threaded end portion for threadedly engaging with athreaded attachment, such as a brass pipe or the like.

At least one advantage of the first body having an overlapping portionand a non-overlapping portion is that the non-overlapping portion can bechanged without requiring a corresponding change to the shape of thesecond body. For example, the first body could be formed to incorporatemale or female threaded end portions of different sizes, whilemaintaining the same size and shape of the overlapping portion of thecylindrical wall. This would allow the same mold for the second body tobe used in conjunction with any configuration of the first body, thusproviding increased options and flexibility during manufacturing.

The cylindrical wall preferably has at least one circumferential groovethat extends radially inwardly from the outer circumferential surface,and more preferably at least two circumferential grooves. The secondbody is preferably overmolded over the circumferential grooves, therebyforming circumferential fingers that extend into and engage with thecircumferential grooves. The engagement of the circumferential grooveswith the circumferential fingers helps to resist the second body beingseparated from the first body.

Preferably, at least one of the circumferential grooves carries aresiliently compressible o-ring, which provides a fluid tight sealbetween the cylindrical wall and the second body. This helps to preventfluid from leaking out of the fitting through the space between thefirst body and the second body.

Preferably, the first body is made from a first polymeric material thatis suitable for attachment to a metallic pipe, such as glass-filledpolyvinylidene fluoride. Also preferably the second body is formed froma second polymeric material that is different from the first polymericmaterial, such as polymeric materials that are suitable for attachmentto a polymeric pipe, including chlorinated polyvinyl chloride.

Preferably, the anti-rotation grooves are oriented in a substantiallyparallel pattern on the first interface surface.

In some embodiments, the first body has a cylindrical wall with acylindrical outer surface, a cylindrical inner surface, and aring-shaped end surface that connects the cylindrical outer surface tothe cylindrical inner surface; wherein the cylindrical inner surfacedefines at least part of the first portion of the fluid flow passage;and wherein the ring-shaped end surface comprises the first interfacesurface.

Preferably, the cylindrical wall extends concentrically about a centralaxis; wherein the first internal opening comprises a circular opening;and wherein the central axis extends through a center of the circularopening.

In some embodiments, the end surface, which is preferably ring-shaped,comprises a top surface that is substantially perpendicular to thecentral axis; wherein each of the anti- rotation grooves has a firstside surface, a second side surface, and a bottom surface; wherein thefirst side surface and the second side surface each extend axiallyinwardly from the top surface, the first side surface being spaced fromand substantially parallel to the second side surface; wherein thebottom surface is spaced axially inwardly from the top surface andextends between the first side surface and the second side surface; andwherein the first side surface, the second side surface, the bottomsurface and the groove end surface of each anti-rotation groove definesa groove cavity.

Optionally, the bottom surface of each of the anti-rotation grooves issubstantially flat, and substantially parallel to the top surface. Thefirst side surface and the second side surface optionally each have asubstantially flat portion. The substantially flat portion of the firstside surface and the substantially flat portion of the second sidesurface may, for example, be substantially perpendicular to the topsurface. Optionally, the first side surface and the second side surfaceeach have a rounded transition portion that connects the substantiallyflat portion to the top surface.

In some embodiments, the first interface surface has a bearing areawhere the anti-rotation grooves contact with the anti-rotation fingersto resist rotation of the second body about the central axis relative tothe first body; wherein the bearing area is related to an expectedmagnitude of torque applied to the pipe fitting during installation ofthe pipe fitting according to the following equation: T=C×BA wherein Trepresents the expected magnitude of torque in pound inches, BArepresents the bearing area in square inches, and C represents aconstant in pounds per inch; and wherein the constant C is in a rangefrom 2000 pounds per inch to 2400 pounds per inch. Optionally, each ofthe anti-rotation grooves has a vertical surface area that includes thefirst side surface and the second side surface; and wherein the bearingarea is calculated as 50% of a sum of the vertical surface areas of theanti-rotation grooves. The constant C may, for example, be between 2100pounds per inch and 2200 pounds per inch, or between 2125 pounds perinch and 2135 pounds per inch, or about 2129.17.

In some embodiments, each of the anti-rotation grooves has a widthdefined by a distance between the first side surface and the second sidesurface; wherein each of the anti-rotation grooves has a depth definedby an axial distance of the bottom surface from the top surface; andwherein a ratio of the width to the depth is, for example, in a rangefrom 1.45 to 1.55, or between 1.50 and 1.52, or about 1.516. Optionally,the width of each of the anti-rotation grooves is substantiallyidentical; and the depth of each of the anti-rotation grooves issubstantially identical.

In some embodiments, the anti-rotation grooves each extend from thecylindrical outer surface of the cylindrical wall towards a centralplane that contains the central axis and is substantially perpendicularto the anti-rotation grooves. The anti-rotation grooves may, forexample, each have a groove end surface that extends axially inwardlyfrom the top surface to the bottom surface, and that extends between thefirst side surface and the second side surface; and wherein the grooveend surface of each of the anti-rotation grooves is spaced from thecentral plane, and spaced from the circular opening. Optionally, theanti-rotation grooves on a first side of the central plane aresymmetrical relative to the anti-rotation grooves on a second side ofthe central plane. Optionally, there are at least 3 and no more than 11of the anti-rotation grooves on each side of the central plane, or thereare at least 5 and no more than 9 of the anti-rotation grooves on eachside of the central plane, or there are 7 of the anti-rotation grooveson each side of the central plane. Preferably, the groove end surface ofeach of the anti-rotation grooves is rounded. The groove end surface ofeach of the anti-rotation grooves may, for example, be spaced a radialdistance from the cylindrical inner surface; wherein the cylindricalwall has a wall thickness defined by a distance between the cylindricalouter surface and the cylindrical inner surface; and wherein a ratio ofthe radial distance to the wall thickness is greater than 0.3, orbetween 0.3 and 0.5, or between 0.35 and 0.45, or about 0.395. In somepreferred embodiments, the radial distance of the groove end surface ofeach of the anti-rotation grooves from the circular opening issubstantially equal.

Preferably, the second body has a cylindrical extension that extendsconcentrically about the central axis; and wherein the cylindricalextension has an inner extension surface that engages with thecylindrical outer surface of the cylindrical wall. The cylindrical wallpreferably has at least one circumferential groove that extends radiallyinwardly from the cylindrical outer surface. The cylindrical extensionis preferably overmolded over at least a portion of the cylindricalouter surface, including the at least one circumferential groove. The atleast one circumferential groove optionally comprises a sealing groovethat contains a resiliently compressible o-ring, the o-ring beingconfigured to provide a fluid tight seal between the cylindrical walland the cylindrical extension. Optionally, the cylindrical extension hasa circumferential finger that extends radially inwardly from the innerextension surface; wherein the at least one circumferential groovecomprises a retaining groove that receives and engages with thecircumferential finger; and wherein axial movement of the second bodyrelative to the first body is resisted by the engagement of thecircumferential finger with the retaining groove.

Preferably, the second end of the fluid flow passage is axially spacedfrom the first body and/or the first end of the fluid flow passage isaxially spaced from the second body.

Optionally, the first body has a threaded end portion for threadedlyengaging with a threaded attachment; and wherein the threaded endportion defines the first end of the fluid flow passage. The threadedend portion may, for example, comprise a male threaded end portion or afemale threaded end portion.

Optionally, the second body has a cylindrical end portion for engagingwith a cylindrical attachment; and wherein the cylindrical end portiondefines the second end of the fluid flow passage. The cylindrical endportion may, for example, comprise a spigot or a socket.

Preferably, the first body is formed from a first polymeric material,and the second body is formed from a second polymeric material; whereinthe first polymeric material differs from the second polymeric material.The first polymeric material may, for example, comprise polyvinylidenefluoride, polyphenylene sulfide, polyvinyl chloride, chlorinatedpolyvinyl chloride, or polyphenylsulfone. Preferably, the firstpolymeric material contains reinforcing fibers. The reinforcing fibersmay, for example, comprise glass fibers. The second polymeric materialmay, for example, comprise chlorinated polyvinyl chloride.

Preferably, the first body comprises a molded first body. The secondbody is preferably overmolded over at least a portion of the first body,including the first interface surface.

In preferred embodiments, the pipe fitting is a composite transitionfitting for fluidly connecting, via the first portion and the secondportion of the fluid flow passage, a first fluid conduit formed from afirst material and a second fluid conduit formed from a second materialwhich differs from the first material. Optionally, the first bodyconnects to the first fluid conduit at the first end of the fluid flowpassage, the first fluid conduit being formed from a metallic material;and wherein the second body connects to the second fluid conduit at thesecond end of the fluid flow passage, the second fluid conduit beingformed from a polymeric material.

Preferably, the pipe fitting is lead-free and/or metal-free.

In some embodiments, the first body comprises an overlapping portion anda non-overlapping portion; wherein the second body is overmolded overthe overlapping portion; wherein the second body is spaced from thenon-overlapping portion; and wherein the first end of the fluid flowpassage is defined by the non-overlapping portion. Optionally, thesecond body comprises an attachment portion and an extension portion;wherein the attachment portion is attached to the overlapping portion ofthe first body; wherein the extension portion is spaced from the firstbody; and wherein the second end of the fluid flow passage is defined bythe extension portion.

In another aspect, the present invention resides in a method ofproducing a pipe fitting, the pipe fitting comprising: a first body anda second body that together at least partially define a fluid flowpassage; the first body defining a first portion of the fluid flowpassage that extends from a first end of the fluid flow passage to afirst internal opening; the second body defining a second portion of thefluid flow passage that extends from a second internal opening to asecond end of the fluid flow passage; wherein the first body has a firstinterface surface that radially surrounds the first internal opening,the first interface surface having a plurality of anti-rotation grooves;wherein the second body has a second interface surface that radiallysurrounds the second internal opening and engages with the firstinterface surface, the first internal opening being in fluidcommunication with the second internal opening, and the second interfacesurface having a plurality of anti-rotation fingers that are eachreceived by and engage with a corresponding one of the anti-rotationgrooves; and wherein rotation of the second body relative to the firstbody is resisted by the engagement of the anti-rotation fingers with theanti-rotation grooves; the method comprising: producing the first body;and overmolding the second body over at least a portion of the firstbody, including the first interface surface. Preferably, producing thefirst body comprises injection molding the first body.

Further aspects of the invention will become apparent upon reading thefollowing detailed description and drawings, which illustrate theinvention and preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which illustrate embodiments of the invention:

FIG. 1 is a perspective view of a pipe fitting in accordance with afirst embodiment of the present invention;

FIG. 2 is an exploded perspective view of the pipe fitting of FIG. 1,showing a first body, a second body, and an o-ring of the pipe fitting;

FIG. 3 is an exploded perspective view showing the pipe fitting of FIG.1 positioned for attachment to a threaded fitting and a non-threadedpolymeric pipe;

FIG. 4 is a perspective view of the first body shown in FIG. 2;

FIG. 5 is a side view of the first body shown in FIG. 4;

FIG. 6 is a top view of the first body shown in FIG. 4;

FIG. 7 is an enlarged view of an anti-rotation groove of the first bodyshown in FIG. 4;

FIG. 8 is a cross-sectional view of the first body shown in FIG. 4,taken along line A-A′ shown in FIG. 4;

FIG. 9 is a perspective view of the second body shown in FIG. 2;

FIG. 10 is an enlarged view of an anti-rotation finger of the secondbody shown in FIG. 9;

FIG. 11 is a cross-sectional view of the pipe fitting of FIG. 1, takenalong line B-B′ shown in FIG. 1;

FIG. 12 is an enlarged cross-sectional view showing the o-ringpositioned between the first body and the second body in the pipefitting as shown in FIG. 11;

FIG. 13 is a perspective view of a pipe fitting in accordance with asecond embodiment of the invention having a female threaded end portion;

FIG. 14 is a perspective view of a first body of the pipe fitting shownin FIG. 13; and

FIG. 15 is a cross-sectional view of the first body shown in FIG. 14,taken along line C-C′ as shown in FIG. 14.

DETAILED DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention and its advantages can beunderstood by referring to the present drawings. In the presentdrawings, like numerals are used for like and corresponding parts of theaccompanying drawings. Also, the following preferred embodiments anddetailed description illustrate and describe non-limiting features ofthe invention.

FIGS. 1 and 2 show a composite transition pipe fitting 10 in accordancewith a first embodiment of the invention. As can be seen in FIG. 2, thepipe fitting 10 has a polymeric first body 12, a polymeric second body14, and a resiliently compressible o-ring 16.

The first body 12 is shown in FIGS. 4 and 5 as including an interfaceportion 18, a tool engagement portion 20, and a threaded end portion 22.As can be seen in FIG. 8, a cylindrical passageway 24 extends throughthe first body 12 along a central axis 26. The cylindrical passageway 24has a first open end 28 that is defined by the interface portion 18 anda second open end 30 that is defined by the threaded end portion 22.

The interface portion 18 of the first body 12 has a wall 32 that extendsabout the central axis 26. As can be seen in FIG. 4, the wall 32 has anouter surface 34, an inner surface 36, and an end surface 38 thatsurrounds the first open end 28 of the cylindrical passageway 24 andspans between the outer surface 34 and the inner surface 36. The endsurface 38 is also referred to herein as the first interface surface 38.Optionally, the wall 32 is a cylindrical wall 32 that extendsconcentrically about the central axis 26, as is shown in FIG. 4,although this is not necessary. In other embodiments, the wall 32 couldhave any desired shape, including for example an oval or square shape.With respect to the embodiment shown, in which the wall 32 is acylindrical wall 32, the outer surface 34 is also referred to herein asa cylindrical outer surface 34; the inner surface 36 is also referred toherein as a cylindrical inner surface 36; and the end surface 38 is alsoreferred to herein as a ring-shaped end surface 38. A firstcircumferential groove 40 and a second circumferential groove 42 extendradially inwardly from the cylindrical outer surface 34 towards thecentral axis 26, as can be seen in FIG. 5.

As shown in FIG. 4, the ring-shaped end surface 38 has a top surface 46that is substantially perpendicular to the central axis 26, and aplurality of anti-rotation grooves 44. As best seen in FIG. 7, each ofthe anti-rotation grooves 44 preferably has a first side surface 48, asecond side surface 50, a groove end surface 52, and a bottom surface54.

The first side surface 48 and the second side surface 50 each extendaxially inwardly from the top surface 46, with the first side surface 48being spaced from and substantially parallel to the second side surface50. The first side surface 48 and the second side surface 50 each have asubstantially flat portion 56 that is substantially perpendicular to thetop surface 46, and a rounded transition portion 58 that connects thesubstantially flat portion 56 to the top surface 46.

The bottom surface 54 is spaced axially inwardly from the top surface46, and extends between the first side surface 48 and the second sidesurface 50. Preferably, the bottom surface 54 is substantially flat, andsubstantially parallel to the top surface 46. The groove end surface 52extends axially inwardly from the top surface 46 to the bottom surface54, and extends between the first side surface 48 and the second sidesurface 50. The groove end surface 52 is preferably rounded. Together,the first side surface 48, the second side surface 50, the groove endsurface 52, and the bottom surface 54 define a groove cavity 60.

Each of the anti-rotation grooves 54 have a width 64 defined by thedistance between the first side surface 48 and the second side surface50, as measured along the bottom surface 54, and a depth 66 defined bythe axial distance of the bottom surface 54 from the top surface 46.Preferably, a ratio of the width 64 to the depth 66 is in a range from1.45 to 1.55, or between 1.50 and 1.52, or about 1.516.

As can be seen in FIG. 6, the anti-rotation grooves 44 are preferablyoriented in a substantially parallel pattern on the ring-shaped endsurface 38, with each of the anti-rotation grooves 44 extending from thecylindrical outer surface 34 towards a central plane 62 that containsthe central axis 26 and is substantially perpendicular to theanti-rotation grooves 44. In the embodiment shown, there are sevenanti-rotation grooves 44 arranged on each side of the central plane 62,with the anti-rotation grooves 44 on a first side of the central plane62 being substantially symmetrical relative to the anti-rotation grooves44 on a second side of the central plane 62.

As can be seen in FIG. 6, the first open end 28 of the cylindricalpassageway 24 is preferably a circular opening 29, with the central axis26 extending through a center of the circular opening 29. A slopedtransition surface 68 surrounds the circular opening 29, and connectsthe top surface 46 of the cylindrical wall 32 to the cylindrical innersurface 36, as shown in FIG. 8.

The groove end surface 52 of each anti-rotation groove 44 is spaced aradial distance 72 from the first open end 28. The radial distance 72 ismeasured as the distance between the groove end surface 52 and thecylindrical inner surface 36, as shown in FIG. 8. The cylindrical wall32 has a wall thickness 70 defined by a distance between the cylindricalouter surface 34 and the cylindrical inner surface 36. Preferably, aratio of the radial distance 72 to the wall thickness 70 is greater than0.3, or between 0.3 and 0.5, or between 0.35 and 0.45, or about 0.395.

As can be seen in FIG. 3, the tool engagement portion 20 is positionedbetween the interface portion 18 and the threaded end portion 22 of thefirst body 12. The tool engagement portion 20 extends radially outwardlyfrom the cylindrical wall 32, and has a generally hexagonal shape thatis selected for engagement with a suitable tool such as a wrench or thelike.

The threaded end portion 22 extends axially away from the toolengagement portion 20, and has a male threaded connection 74 forthreadedly engaging with a suitable female threaded attachment. The malethreaded connection 74 may have any suitable size and shape, andpreferably incorporates molded tapered threads that conform to thenational pipe thread (NTP) standards. Optionally, the threads may rangein size from ½ inch to 2 inches, for example. Other thread sizes couldalso be used.

As can be seen in FIGS. 1 and 2, the second body 14 has an engagementportion 76 and a cylindrical end portion 78. The cylindrical end portion78 defines an internal passageway 84 that extends along the central axis26 from a first open end 86 to a second open end 88, as shown in FIG.11. The engagement portion 76 has a ring-shaped second interface surface80 that surrounds the first open end 86 of the internal passageway 84,as is best shown in FIG. 9, and a cylindrical extension 82 that extendsfrom the second interface surface 80 away from the cylindrical endportion 78.

The cylindrical extension 82 extends concentrically about the centralaxis 26, and has an inner extension surface 92 that faces radiallyinwardly. A circumferential finger 94 extends radially inwardly from theinner extension surface 92. As can be seen in FIG. 11, the innerextension surface 92 engages with the cylindrical outer surface 34 ofthe first body 12, with the first circumferential groove 40 receivingand engaging with the circumferential finger 94. The engagement of thefirst circumferential groove 40 with the circumferential finger 94resists axial movement of the second body 14 relative to the first body12. As can be seen in FIG. 11, the o-ring 16 is positioned within thesecond circumferential groove 42 and is compressed between thecylindrical wall 32 and the cylindrical extension 82 to provide a fluidtight seal therebetween.

As shown in FIG. 9, the second interface surface 80 has a plurality ofanti-rotation fingers 90 that extend radially inwardly from the innerextension surface 92 towards the first open end 86 of the internalpassageway 84. The anti-rotation fingers 90 each have a shape and sizethat corresponds to the shape and size of the groove cavity 60 of acorresponding one of the anti-rotation grooves 44. The second interfacesurface 80 of the second body 14 engages with the first interfacesurface 38 of the first body 12, with the anti-rotation fingers 90 eachbeing received by and engaging with the corresponding anti-rotationgrooves 44. The engagement of the anti-rotation fingers 90 with theanti-rotation grooves 44 resists rotation of the second body 14 relativeto the first body 12 about the central axis 26.

As best shown in FIG. 11, the cylindrical passageway 24 of the firstbody 12 and the internal passageway 84 of the second body 14 togetherform a fluid flow passage 96 that extends through the pipe fitting 10,with the cylindrical passageway 24 forming a first portion of the fluidflow passage 96 and the internal passageway 84 forming a second portionof the fluid flow passage 96. The second open end 30 of the cylindricalpassageway 24 forms a first end 100 of the fluid flow passage 96; thefirst open end 28 of the cylindrical passageway 24 forms a firstinternal opening 98 of the fluid flow passage 96; the first open end 86of the internal passageway 84 forms a second internal opening 102 of thefluid flow passage 96 that is aligned with and in fluid communicationwith the first internal opening 98; and the second open end 88 of theinternal passageway 84 forms a second end 104 of the fluid flow passage96.

Preferably, the pipe fitting 10 is produced in the following manner. Ina first step, the first body 12 is molded from a first polymericmaterial, for example by injection molding. Preferably, the firstpolymeric material is polyvinylidene fluoride containing glassreinforcing fibers. Once the first body 12 has hardened, in a secondstep the diaphragm gate is removed. In a third step the o-ring 16 isplaced into the first circumferential groove 40. Once the o-ring 16 isin place, in a fourth step the second body 14 is overmolded over theinterface portion 18 of the first body 12, for example by injectionmolding. Once the second body 14 has hardened, the diaphragm gate isremoved. The second body 14 is formed from a second polymeric materialthat differs from the first polymeric material. Preferably, the secondpolymeric material is chlorinated polyvinyl chloride.

During the overmolding of the second body 14 over the interface portion18 of the first body 12, the molten second polymeric material flows overthe cylindrical outer surface 34 of the cylindrical wall 32, and intothe second circumferential groove 42. The second polymeric material thatsurrounds the cylindrical outer surface 34 forms the cylindricalextension 82 of the second body 14, and the second polymeric materialthat fills the second circumferential groove 42 forms thecircumferential finger 94. Because the cylindrical extension 82 isformed by overmolding over the cylindrical outer surface 34, the contourof the inner extension surface 92 of the cylindrical extension 82precisely matches the contour of the cylindrical outer surface 34, andthe contour of the circumferential finger 94 precisely matches thecontour of the second circumferential groove 42, thereby forming astrong, leak resistant fit.

Preferably, the o-ring 16 is selected so that it does not completelyfill the first circumferential groove 40, as shown in FIG. 12. Thisleaves space for the second polymeric material to flow into the firstcircumferential groove 40 during the overmolding, thereby forming asecondary circumferential finger 106 shown best in FIG. 12 that extendsinto the first circumferential groove 40 and abuts against the o-ring16. As the second polymeric material is injected into the firstcircumferential groove 40, the o-ring 16 is compressed by the pressureof the second polymeric material. The compressed o-ring 16 forms a fluidtight seal between the secondary circumferential finger 106 and thefirst circumferential groove 40, and thus helps to prevent leaks. Theengagement of the secondary circumferential finger 106 with the firstcircumferential groove 40 furthermore helps to resist axial movement ofthe second body 14 relative to the first body 12.

During the overmolding process, the second polymeric material also flowsover the first interface surface 38, and into the anti-rotation grooves44. The second polymeric material that covers the first interfacesurface 38 forms the second interface surface 80 of the second body 14,and the second polymeric material that fills the anti-rotation grooves44 forms the anti-rotation fingers 90. Because the second interfacesurface 80 is formed by overmolding over the first interface surface 38,the contour of the second interface surface 80 precisely matches thecontour of the first interface surface 38, and the contour of theanti-rotation fingers 90 precisely matches the contour of theanti-rotation grooves 44, thereby forming a strong, leak resistant fit.

Once the second body 14 hardens and the diaphragm gate is removed, thepipe fitting 10 is ready for use. The pipe fitting 10 is most preferablyused as a composite transition fitting for fluidly connecting, via thefluid flow passage 96, a first fluid conduit formed from a metallicmaterial and a second fluid conduit formed from a polymeric material.For example, as shown in FIG. 3, the pipe fitting 10 can be used tofluidly connect a pump 108 having a metallic (brass) threaded attachmentor fitting 110 to a polymeric water distribution pipe 112. To connectthe pipe fitting 10 to the metallic threaded attachment 110, the malethreaded end portion 22 of the first body 12 is inserted into the femalemetallic threaded attachment 110, and the pipe fitting 10 is rotated,for example by a wrench or a similar tool that engages with the toolengagement portion 20, to thereby form a fluid tight threadedconnection. To connect the pipe fitting 10 to the polymeric waterdistribution pipe 112, the polymeric water distribution pipe 112 isinserted into the first open end 86 of the internal passageway 84 of thesecond body 14. A water-tight seal is formed between the polymeric waterdistribution pipe 112 and the second body 14 by, for example, applying asolvent cement to form a chemical weld. Once the pipe fitting 10 isinstalled in place, water or other fluids can flow between the pump 108and polymeric water distribution pipe 112 via the fluid flow passage 96provided by the pipe fitting 10.

The pipe fitting 10 is thus able to fluidly connect a metallic componentto a polymeric component, without incorporating any metallic materialsinto the pipe fitting 10 itself. This can help to reduce costs, asmetallic parts such as machined brass alloy can be very expensive.Furthermore, the pipe fitting 10 is completely lead free, and can thusbe used for potable water systems without raising concerns about leadcontamination.

The first body 12 is preferably formed from polyvinylidene fluoridecontaining glass reinforcing fibers. This material is advantageous dueto its resistance to chemicals and its ability to retain good mechanicalproperties at high temperatures. Furthermore, polyvinylidene fluoridehas a low difference in coefficient of thermal expansion when comparedto chlorinated polyvinyl chloride. This helps to prevent leaks when thepipe fitting 10 is subjected to cyclic thermal loading, for example whenused in a hot and cold water system. In contrast, when dissimilarmaterials such as brass and chlorinated polyvinyl chloride are combinedtheir wide spread in coefficients of thermal expansion can lead to aleak path between the materials when thermally loaded or resulting fromthermocycling.

The construction of the pipe fitting 10 allows it to withstand variousaxial and torsional forces that may be experienced during installationand/or operation. For example, axial forces may occur from thermalexpansion or contraction, operating pressures, water hammer or otherpressure fluctuations. The strong mechanical connection that is createdby molding the circumferential finger 94 and the secondarycircumferential finger 106 into the first and second circumferentialgrooves 40, 42 allows the pipe fitting 10 to resist these axial forces,and prevent the second body 14 from being axially separated from thefirst body 12.

The pipe fitting 10 may also experience torsional forces that attempt torotate the first body 12 relative to the second body 14, for exampleduring the installation and/or removal of the threaded end portion 22from a threaded attachment. The engagement of the anti-rotation fingers90 with the anti-rotation grooves 44 allows the pipe fitting 10 toresist these torsional forces, and prevent the first body 12 fromrotating relative to the second body 14.

The anti-rotation fingers 90 and the anti-rotation grooves 44 have aunique geometry that is designed to maximize surface area contactbetween the first body 12 and the second body 14, and to distribute thetorsional forces created during installation and disassembly across thebearing area of the fitting 10. This in turn reduces stressconcentrations, resulting in a robust fitting 10.

Preferably, the number, size, shape, depth 66, length, and/or width 64of the anti-rotation grooves 44 and the anti-rotation fingers 90 isselected so that there is a relationship between the expected torsionalforces (torque) experienced during installation and/or disassembly andthe bearing area that is defined by the following formula: T=C×BA.

In this formula T is torque, or the forces generated duringinstallation. The bearing area is expressed as BA. The bearing area isthe surface area of the anti-rotation features that are subjected toforces during installation. The bearing area is calculated as 50% of asum of the vertical surface areas of the anti-rotation grooves 44,including the first side surfaces 48 and the second side surfaces 50 andthe radii of the rounded groove end surfaces 52. This can be calculatedusing measuring tools within a 3-D CAD software package, measurementsand hand calculations, or other equivalent means. C is a constant valuethat is maintained as fitting size, and thus installation forces,increase or decrease. The constant value C is preferably in a range from2000 pounds per inch to 2400 pounds per inch, or between 2100 pounds perinch and 2200 pounds per inch, or between 2125 pounds per inch and 2135pounds per inch, or about 2129 pounds per inch.

By way of example, the preferred bearing area of a pipe fitting 10 inaccordance with the invention, wherein the pipe fitting 10 is expectedto experience up to 600 inch pounds of torque during installation andthe constant value is selected as 2129 pounds per inch, would becalculated as follows: BA=T (600 inch pounds)/C (2129 pounds perinch=0.2818 square inches. The number, size, shape, depth 66, length,and/or width 64 of the anti-rotation grooves 44 and the anti-rotationfingers 90 for this fitting 10 would thus be selected so that the totalbearing area was about 0.2818 square inches.

As mentioned above, the ratio of the width 64 and the depth 66 of theanti-rotation grooves 44 is preferably in a range from 1.45 to 1.55, orbetween 1.50 and 1.52, or most preferably about 1.516. Having a ratiobetween the width 64 and the depth 66 of about 1.516 helps to ensurethat the anti-rotation grooves 44 and the anti-rotation fingers 90 haveadequate strength to withstand the torsional forces present duringinstallation and/or disassembly as well as use. For example, in somepreferred embodiments the width 64 of the anti-rotation grooves 44 isabout 0.0955 inches and the depth 66 is about 0.0630 inches, providing awidth 64 to depth 66 ratio of about 1.516.

As mentioned above, each of the anti-rotation grooves 44 is spaced aradial distance 72 from the first internal opening 98, wherein the ratioof the radial distance 72 to the wall thickness 70 is preferably greaterthan 0.3, or between 0.3 and 0.5, or between 0.35 and 0.45, or mostpreferably about 0.395. The radial distance 72 that the anti-rotationgrooves 44 are spaced from the first internal opening 98 provides anundisturbed concentric circle of the first polymeric material,preferably polyvinylidene fluoride, surrounding the first internalopening 98. This helps to maintain the integrity of the fitting 10 byensuring a suitable ring of stronger polyvinylidene fluoride is adjacentto the fluid flow passage 96, rather than alternating betweenpolyvinylidene fluoride and chlorinated polyvinyl chloride. Having theanti-rotation grooves 44 spaced from the first internal opening 98 alsoeliminates many potential leak paths. Having a ratio of the radialdistance 72 to the wall thickness 70 of about 0.395 provides a balancebetween strength of the cylindrical wall 32 and strength of theanti-rotation features. A larger ratio would improve the strength of thecylindrical wall 32, but reduce the strength of the anti-rotationgrooves 44 and the anti-rotation fingers 90 by reducing the bearingarea. A lower ratio would reduce the strength of the cylindrical wall32, but increase the strength of the anti-rotation grooves 44 and theanti-rotation fingers 90. In one exemplary embodiment, each of theanti-rotation grooves 44 is spaced a radial distance 72 from the firstinternal opening 98 of about 0.128 inches, and the wall thickness 70 ofthe cylindrical wall 32 is about 0.324 inches. The resulting ratio ofthe radial distance 72 to the wall thickness 70 is about 0.395.

A further advantage of the pipe fitting 10 in accordance with thepresent invention is that the threaded end portion 22 of the first body12 is spaced from the cylindrical end portion 78 of the second body 14.As such, the shape and size of the threaded end portion 22 is notdependent on the shape and size of the cylindrical end portion 78, andthe threaded end portion 22 and the cylindrical end portion 78 can beselected independently from one another. As described in more detailbelow, this provides increased options and flexibility duringmanufacturing of the pipe fitting 10.

As previously described, the second body 14 is preferably overmoldedonto the interface portion 18 of the first body 12. The interfaceportion 18 can thus be described as an overlapping portion of the firstbody 12, because it overlaps with the second body 14. The toolengagement portion 20 and the threaded end portion 22 are spaced fromthe second body 14, and can thus be described as a non-overlappingportion of the first body 12. Similarly, the cylindrical extension 82 ofthe second body 14 is attached to the first body 12, and can thus bedescribed as an attachment portion of the second body 14. Because thecylindrical end portion 78 of the second body 14 is spaced from thefirst body 12, it can be described as an extension portion of the secondbody 14.

This configuration of the pipe fitting 10, with the first body 12 havingan overlapping portion and a non-overlapping portion and the second body14 having an attachment portion and an extension portion, wherein thenon-overlapping portion defines the first end 100 of the fluid flowpassage 96 and the extension portion defines the second end 104 of thefluid flow passage 96, provides a number of advantages duringmanufacturing. For example, because the first end 100 of the fluid flowpassage 96 does not overlap with the second body 14, the first end 100can be selected to have any desired shape or configuration, includingfor example a male or female design of various sizes, without requiringany changes to the shape and size of the overlapping portion. As such,in a manufacturing process wherein a variety of different pipe fittings10 are being produced with different sizes and shapes of thenon-overlapping portion of the first body 12, the same mold can be usedto overmold the second body 14 over each of the different first body 12designs. This significantly simplifies the manufacturing process, andallows for a wide variety of pipe fitting 10 designs to be manufacturedat relatively low cost.

Similarly, because the second end 104 of the fluid flow passage 96 doesnot overlap with the first body 12, the second end 104 can be selectedto have any desired shape or configuration, including for example aspigot or a socket design of various sizes, without requiring anychanges to the shape and size of the attachment portion. As such, avariety of different molds for the second body 14 could be used inconjunction with a variety of different molds for the first body 12,with the attachment portion of the second body 14 and the overlappingportion of the first body 12 remaining constant, and the extensionportion of the second body 14 and the non-overlapping portion of thefirst body 12 varying. In this way, a wide variety of differentconfigurations of the pipe fitting 10 could be manufactured relativelyeasily, including any suitable combination of male/female andsocket/spigot of various sizes. For example, a pipe fitting 10 inaccordance with the invention could incorporate a ¾ inch male threadedend portion 22 on the first body 12 with a 1 inch socket at the secondopen end 88 of the second body 14, or any other suitable combination.

To illustrate just one of the many possible alternative configurations,a pipe fitting 10 in accordance with a second embodiment of theinvention is shown in FIGS. 13 to 15. The pipe fitting 10 as shown inFIGS. 13 to 15 is identical to the pipe fitting 10 shown in FIGS. 1 to12, with the only difference being that a threaded end portion 122 ofthe first body 12 is female instead of male. As the interface portion 18of the first body 12 is unchanged, the same mold for the second body 14could be used to produce both the pipe fitting shown in FIGS. 13 to 15and the pipe fitting 10 shown in FIGS. 1 to 12.

It will be understood that, although various features of the inventionhave been described with respect to one or another of the embodiments ofthe invention, the various features and embodiments of the invention maybe combined or used in conjunction with other features and embodimentsof the invention as described and illustrated herein.

The pipe fitting 10 in accordance with the present invention is notlimited to the particular construction shown in the drawings. Forexample, in alternative embodiments the anti-rotation grooves 44 couldextend radially inwardly towards the central axis 26, rather than beingparallel. The anti-rotation grooves 44 can be considered to be parallelwhen a longitudinal centerline 114 of each groove 44 is parallel withthe longitudinal centerline 114 of the other grooves 44, as shown inFIG. 6. The anti-rotation grooves 44 could also have a different shapethan the one shown in the drawings, and for example the groove endsurface 52 could be flat instead of rounded; the bottom surface 54 couldbe rounded instead of flat; and the first and second side surfaces 48,50 could be entirely flat, entirely rounded, angled upwardly ordownwardly relative to the central axis 26, or have any other desiredshape and orientation. It is preferable, though not required, that eachanti-rotation groove 44 is substantially symmetric about itslongitudinal centerline 114.

The anti-rotation grooves 44 and the anti-rotation fingers 90 arepreferably in the line of draw of the mold opening, which allows theanti-rotation features to be molded. The anti-rotation features are alsopreferably designed to provide a gentle flow path for the molten polymerto flow into and fill the features. Rounded edges are preferably used toprovide a favorable geometry for the overmolding operation. Although thepipe fitting 10 is preferably produced by injection molding the firstbody 12, placing the o-ring 16 in the first circumferential groove 40,and then overmolding the second body 14 by injection molding over thefirst body 12, any other suitable method of producing the pipe fitting10 could also be used. The number of anti-rotation grooves 44 could alsobe higher or lower than the number shown in the drawings. The pipefitting 10 could also have a higher number or a lower number ofcircumferential grooves 40, 42. In some alternative embodiments, theo-ring 16 could be omitted. In other embodiments, there could be morethan one o-ring 16.

Although the first body 12 has been described as preferably being formedfrom polyvinylidene fluoride containing glass reinforcing fibers, aperson skilled in the art would appreciate that other materials could beused instead. For example, the first body 12 could alternatively beformed from polyphenylene sulfide, polyvinyl chloride, chlorinatedpolyvinyl chloride, or polyphenylsulfone, with or without reinforcingfibers. The material from which the first body 12 is formed ispreferably selected based on the expected operating conditions,including for example the type of material that the first body 12 willbe connected to, the system pressure and temperature, and the fluid thatwill pass through the fluid flow passage 96. The first body 12 couldalso contain any suitable type of reinforcing fibers, including forexample carbon, stainless steel, aramid, basalt, and/or polyester.

The second body 14 is also not limited to being formed from chlorinatedpolyvinyl chloride, as described in the preferred embodiments. Rather,any suitable material could be used including, for example, polyvinylchloride, polyethylene, polypropylene, polyvinylidene fluoride, and/orcross-linked polyethylene.

Preferably, the first body 12 is produced using a diaphragm or disk gateat a location selected so that the first body 12 is free of weld lines.In a molded part the strength at weld lines is reduced significantly dueto the lack of polymer chain entanglement. The degree of strengthreduction is dependent on the weld line meeting angle. This technicalconcern is preferably eliminated with the use of a diaphragm or diskgate located at the end of the part, for example at the first open end28 of the cylindrical passageway 24.

When a filler, such as glass, is added to a polymer, the result is anoverall increase in material strength. This however is not the case atthe knit or weld line. In these areas the strength is compromised due tothe inability of the fibers to properly mesh. Elimination of the weldlines mitigates this issue.

Gas (air) can become trapped at the meeting of melt fronts in atraditionally gated polymer component. By gating at the end of the part,all gas with the potential to become trapped is pushed by the melt frontto the end of the part where it is able to be vented to atmospherethrough vents in the injection mold. The result is a component withuniformly distributed fibers and consistent mechanical strengththroughout. Preferably, the second body 14 is also produced using adiaphragm or disk gate at a location selected so that the second body 14is free of weld lines, such as at the center of the part, for example atthe first open end 86 of the internal passageway 84.

Although this disclosure has described and illustrated certain preferredembodiments of the invention, it is to be understood that the inventionis not restricted to these particular embodiments. Rather, the inventionincludes all embodiments which are functional, chemical, or mechanicalequivalents of the specific embodiments and features that have beendescribed and illustrated herein.

1. A pipe fitting comprising: a first body and a second body thattogether at least partially define a fluid flow passage; the first bodydefining a first portion of the fluid flow passage that extends from afirst end of the fluid flow passage to a first internal opening; thesecond body defining a second portion of the fluid flow passage thatextends from a second internal opening to a second end of the fluid flowpassage; wherein the first body has a first interface surface thatsurrounds the first internal opening, the first interface surface havinga plurality of anti-rotation grooves; wherein the second body has asecond interface surface that surrounds the second internal opening andengages with the first interface surface, the first internal openingbeing in fluid communication with the second internal opening, and thesecond interface surface having a plurality of anti-rotation fingersthat are each received by and engage with a corresponding one of theanti-rotation grooves; and wherein rotation of the second body relativeto the first body is resisted by the engagement of the anti-rotationfingers with the anti-rotation grooves.
 2. The pipe fitting according toclaim 1, wherein the anti-rotation grooves are oriented in asubstantially parallel pattern on the first interface surface.
 3. Thepipe fitting according to claim 1, wherein the first body has a wallextending about a central axis with an outer surface, an inner surface,and an end surface that spans between the outer surface and the innersurface; wherein the inner surface defines at least part of the firstportion of the fluid flow passage; wherein the end surface comprises thefirst interface surface; wherein the first internal opening comprises acircular opening; and wherein the central axis extends through a centerof the circular opening.
 4. The pipe fitting according to claim 3,wherein the end surface comprises a top surface that is substantiallyperpendicular to the central axis; wherein each of the anti-rotationgrooves has a first side surface, a second side surface, and a bottomsurface; wherein the first side surface and the second side surface eachextend axially inwardly from the top surface, the first side surfacebeing spaced from and substantially parallel to the second side surface;wherein the bottom surface is spaced axially inwardly from the topsurface and extends between the first side surface and the second sidesurface; and wherein the first side surface, the second side surface,and the bottom surface of each anti-rotation groove defines a groovecavity.
 5. The pipe fitting according to claim 4, wherein the bottomsurface of each of the anti-rotation grooves is substantially flat, andsubstantially parallel to the top surface; wherein the first sidesurface and the second side surface each have a substantially flatportion; wherein the substantially flat portion of the first sidesurface and the substantially flat portion of the second side surfaceare substantially perpendicular to the top surface; and wherein thefirst side surface and the second side surface each have a roundedtransition portion that connects the substantially flat portion to thetop surface.
 6. The pipe fitting according to claim 5, wherein the firstinterface surface has a bearing area where the anti-rotation groovescontact with the anti-rotation fingers to resist rotation of the secondbody about the central axis relative to the first body; wherein thebearing area is related to an expected magnitude of torque applied tothe pipe fitting during installation of the pipe fitting according tothe following equation: T=C×BA; wherein T represents the expectedmagnitude of torque in pound inches, BA represents the bearing area insquare inches, and C represents a constant in pounds per inch; andwherein the constant C is in a range from 2000 pounds per inch to 2400pounds per inch.
 7. The pipe fitting according to claim 6, wherein eachof the anti-rotation grooves has a vertical surface area that includesthe first side surface and the second side surface; and wherein thebearing area is calculated as 50% of a sum of the vertical surface areasof the anti-rotation grooves.
 8. The pipe fitting according to claim 4,wherein each of the anti-rotation grooves has a width defined by adistance between the first side surface and the second side surface;wherein each of the anti-rotation grooves has a depth defined by anaxial distance of the bottom surface from the top surface; and wherein aratio of the width to the depth is in a range from 1.45 to 1.55.
 9. Thepipe fitting according to claim 8, wherein the anti-rotation grooveseach extend from the outer surface of the wall towards a central planethat contains the central axis and is substantially perpendicular to theanti-rotation grooves; wherein the anti-rotation grooves each have agroove end surface that extends axially inwardly from the top surface tothe bottom surface, and that extends between the first side surface andthe second side surface; wherein the groove end surface of each of theanti-rotation grooves is spaced from the central plane, and spaced fromthe circular opening; wherein the anti-rotation grooves on a first sideof the central plane are symmetrical relative to the anti-rotationgrooves on a second side of the central plane; and wherein the grooveend surface of each of the anti-rotation grooves is rounded.
 10. Thepipe fitting according to claim 9, wherein the wall is a cylindricalwall that extends concentrically about the central axis, with the outersurface being a cylindrical outer surface and the inner surface being acylindrical inner surface of the cylindrical wall; wherein the grooveend surface of each of the anti-rotation grooves is spaced a radialdistance from the cylindrical inner surface of the cylindrical wall;wherein the cylindrical wall has a wall thickness defined by a distancebetween the cylindrical outer surface and the cylindrical inner surface;and wherein a ratio of the radial distance to the wall thickness isgreater than 0.3.
 11. The pipe fitting according to claim 10, whereinthe ratio of the radial distance to the wall thickness is about 0.395.12. The pipe fitting according to claim 10, wherein the second body hasa cylindrical extension that extends concentrically about the centralaxis; wherein the cylindrical extension has an inner extension surfacethat engages with the cylindrical outer surface of the cylindrical wall;and wherein the cylindrical wall has at least one circumferential groovethat extends radially inwardly from the cylindrical outer surface. 13.The pipe fitting according to claim 12, wherein the at least onecircumferential groove comprises a sealing groove that contains aresiliently compressible o-ring, the o-ring being configured to providea fluid tight seal between the cylindrical wall and the cylindricalextension.
 14. The pipe fitting according to claim 13, wherein thecylindrical extension has a circumferential finger that extends radiallyinwardly from the inner extension surface; wherein the at least onecircumferential groove comprises a retaining groove that receives andengages with the circumferential finger; and wherein axial movement ofthe second body relative to the first body is resisted by the engagementof the circumferential finger with the retaining groove.
 15. The pipefitting according to claim 4, wherein the second end of the fluid flowpassage is axially spaced from the first body; wherein the first end ofthe fluid flow passage is axially spaced from the second body; whereinthe first body has a threaded end portion for threadedly engaging with athreaded attachment; wherein the threaded end portion defines the firstend of the fluid flow passage; wherein the second body has a cylindricalend portion for engaging with a cylindrical attachment; and wherein thecylindrical end portion defines the second end of the fluid flowpassage.
 16. The pipe fitting according to claim 1, wherein the firstbody is formed from a first polymeric material, and the second body isformed from a second polymeric material; and wherein the first polymericmaterial differs from the second polymeric material.
 17. The pipefitting according to claim 16, wherein the first polymeric materialcomprises polyvinylidene fluoride, polyphenylene sulfide, polyvinylchloride, chlorinated polyvinyl chloride, or polyphenylsulfone.
 18. Thepipe fitting according to claim 17, wherein the first polymeric materialcontains reinforcing fibers.
 19. The pipe fitting according to claim 18,wherein the reinforcing fibers comprise glass fibers; wherein the firstpolymeric material comprises polyvinylidene fluoride; and wherein thesecond polymeric material comprises chlorinated polyvinyl chloride. 20.The pipe fitting according to claim 1, wherein the pipe fitting is acomposite transition fitting for fluidly connecting, via the firstportion and the second portion of the fluid flow passage, a first fluidconduit formed from a metallic material and a second fluid conduitformed from a polymeric material; wherein the first body connects to thefirst fluid conduit at the first end of the fluid flow passage; andwherein the second body connects to the second fluid conduit at thesecond end of the fluid flow passage.
 21. A method of producing a pipefitting, the pipe fitting comprising: a first body and a second bodythat together at least partially define a fluid flow passage; the firstbody defining a first portion of the fluid flow passage that extendsfrom a first end of the fluid flow passage to a first internal opening;the second body defining a second portion of the fluid flow passage thatextends from a second internal opening to a second end of the fluid flowpassage; wherein the first body has a first interface surface thatradially surrounds the first internal opening, the first interfacesurface having a plurality of anti-rotation grooves; wherein the secondbody has a second interface surface that radially surrounds the secondinternal opening and engages with the first interface surface, the firstinternal opening being in fluid communication with the second internalopening, and the second interface surface having a plurality ofanti-rotation fingers that are each received by and engage with acorresponding one of the anti-rotation grooves; and wherein rotation ofthe second body relative to the first body is resisted by the engagementof the anti-rotation fingers with the anti-rotation grooves; the methodcomprising: producing the first body; and overmolding the second bodyover at least a portion of the first body, including the first interfacesurface.
 22. The method according to claim 21, wherein producing thefirst body comprises injection molding the first body.
 23. The methodaccording to claim 21, wherein the first body comprises an overlappingportion and a non-overlapping portion; wherein the second body isovermolded over the overlapping portion; wherein the second body isspaced from the non-overlapping portion; wherein the first end of thefluid flow passage is defined by the non-overlapping portion; whereinthe second body comprises an attachment portion and an extensionportion; wherein the attachment portion is attached to the overlappingportion of the first body; wherein the extension portion is spaced fromthe first body; and wherein the second end of the fluid flow passage isdefined by the extension portion.
 24. The method according to claim 21,wherein the first body has a cylindrical wall with a cylindrical outersurface, a cylindrical inner surface, and a ring-shaped end surface thatspans between the cylindrical outer surface to the cylindrical innersurface; wherein the cylindrical inner surface defines at least part ofthe first portion of the fluid flow passage; wherein the ring-shaped endsurface comprises the first interface surface; wherein the cylindricalwall extends concentrically about a central axis; wherein the secondbody has a cylindrical extension that extends concentrically about thecentral axis; wherein the cylindrical extension has an inner extensionsurface that engages with the cylindrical outer surface of thecylindrical wall; wherein the cylindrical wall has at least onecircumferential groove that extends radially inwardly from thecylindrical outer surface; and wherein the cylindrical extension isovermolded over at least a portion of the cylindrical outer surface,including the at least one circumferential groove.